1. Field of the Invention
The present invention relates to a water-resistant switching device. More particularly, it relates to construction of a water-resistant pilot switch in which contacts are switched by a rotary lever member.
2. Description of the Related Art
According to construction of a conventional water-resistant pilot switch, there are provided a fixed contact made up of a conductive metal plate, a movable contact which is disposed to oppose the fixed contact and is brought into or out of contact with the fixed contact, and a lever member rotating the movable contact in the direction of the fixed contact in a receiving section of a box-shaped housing made of an insulating material. Further, a cover member, which is also made of an insulating material is mounted so as to cover the receiving section of the housing.
An insertion hole through which an operating part, or one end portion of the lever member, protrudes outwardly from the housing is provided in the cover member, and the operating part is disposed in the insertion hole so as to be movable in the direction it is pressed.
Also, a shield member formed in the shape of a dome from a material such as a rubber sheet is attached to the insertion hole so as to cover the operating part of the lever member. By providing the shield member in the insertion hole, water and droplets are prevented from entering the receiving section of the housing through the insertion hole.
To actuate this conventional water-resistant pilot switch, the operating part is pressed from the above of the shield member by an actuator (control rod) rotatably mounted to one end portion of the housing so that the movable contact inside is rotated in the direction of the fixed contact by the lever member and the switch is turned on when the fixed contact and the movable contact come into contact with each other.
However, in the construction of the conventional water-resistant pilot switch described above, it was necessary to mount the shield member so as to cover the operating part. Therefore, the shield member had to be formed in accordance with the shape of the operating part, which made its shape complicated and mounting procedure troublesome. Thus, processibility of parts and workability of assembly were not good enough to achieve cost cutting.
Also, the conventional pilot switch is so constructed that the operating part of the lever member cannot be pressed directly, and it has to be pressed via the shield member made of elastic rubber or the like. Accordingly, there has been a problem that operating strokes are not even and the on precision of the switch is hard to achieve.
It is therefore an object of the present invention to solve the above-described problem and to provide a water-resistant pilot switch in which the shape of a shield member is simple, processibility of parts and workability in mounting the parts to a housing are good, cost cutting is possible, and the on precision of the switch in action can be improved.
In order to solve the previously described problem, as a first solution, the water-resistant switching device according to the invention comprises: a housing having a receiving section, a fixed contact provided in the receiving section, a movable contact rotatably provided and being brought into or out of contact with the fixed contact, a lever member rotating the movable contact in the direction of the fixed contact, a cover member having an insertion hole through which one end of the lever member protrudes outwardly from the receiving section and being provided on the receiving section of the housing to be engaged therewith, and a shield member shielding the insertion hole; wherein the lever member is engaged with the insertion hole of the cover member in a rotatable manner, and the shield member is shaped like a ring to fit the rim of the insertion hole and is placed between the lever member and the cover member.
As a second solution, a rotation shaft rotatably supported in the insertion hole of the cover member is formed on the lever member and the ring-like shield member is engaged with the rotation shaft.
As a third solution, the lever member comprises a first lever portion disposed inside the receiving section of the housing and a second lever portion connected to the first lever portion and disposed outside the housing, the shield member being engaged with the rotation shaft of the first lever portion.
As a fourth solution, the first lever portion is rotated as a result of the rotation of the second lever portion, and an outer rim of the rotation shaft and an inner rim of the shield member are formed so as to slidably contact each other.